engine dimensions vs horsepower
- Thread starter clstalions
- Start date
- Tags size vs power
I had a book about automotive physics, and it had a similar example of a scaled down engine vs a regular sized engine. Both having the same amount of horsepower in their respective scale, anyways it had almost a page lenght of calculations and ended in the same conclusion... its not the same. Example 15hp in a single cylinder engine vs 15hp in a two piston (Assuming they both have the same bore x stroke).
The nitro engine I showed is rated at 5 hp @ 32000 rpm the truth is no body believes it really puts out 5 horsepower I think the company just outright lied to sell engines my guess is that it puts out slightly less than 2 horsepower but that's a lot of hp for a piston smaller than a dime. Horsepower is the ability to do a certain amount of work this standard should NEVER be scaled down to produce impressive numbers ok with all that said let me return to the original question
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And the answer is that you should use a 2cycle engine perhaps one from one of those pocket bikes
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And the answer is that you should use a 2cycle engine perhaps one from one of those pocket bikes
the 5 hp briggs and the claimed 5 hp rc car engine are in fact in 2 different scales because the dyno used to calculate hp on the rc car engine has a much smaller counterweight than the dyno used on a 5 hp briggs or a 5hp diesel. the scale is different because if you get 200 of those rc engines their combined power would be 400 hp, most big rigs are stock pushing 300 to 500 hp believe it or not so does that mean those rc car engine can pull a 80000 pound trailer down the highway?? no bigger engines run on different scales. but hp is determined on how fast something can push something to a certain speed
Horsepower is a standard I am not saying that some unscupuless people don't lie or use a different scale but they shouldn't because horsepower is horsepower and the formula for it is ver straight forward Horsepower, Horsepower formula, Horsepower conversion, Horsepower definition - HorsePowerSports.com
The size or "scale" of an engine has no bearing on the units. Horsepower is a measure of force(torque) applied over distance and time(RPM) no matter what. A 5,000hp diesel engine makes the same units of horsepower and torque that a 5hp R/C car engine does. The dynos are different sizes, but the units and the size of those units all remain exactly the same. Equations are all over the place to calculate torque or power if you have the two variables.
Assume KB2ROCKET's engine makes an honest 5hp @ 32,000rpm:
.......HP
TQ = ----- x 5252
......RPM
......5.0
TQ = ------ x 5252
.....32,000
TQ = 0.82 ft-lbs.
Now try the same calculation with an engine making 5hp @ 3600rpm.
To answer clstalions's question, most two cycle engines will be dimensionally smaller than a four cycle for the same power output. The two cycle will tend to make peak power at a higher rpm and consequently less peak torque. What will work best depends on what you intend to do with the engine.
Assume KB2ROCKET's engine makes an honest 5hp @ 32,000rpm:
.......HP
TQ = ----- x 5252
......RPM
......5.0
TQ = ------ x 5252
.....32,000
TQ = 0.82 ft-lbs.
Now try the same calculation with an engine making 5hp @ 3600rpm.
To answer clstalions's question, most two cycle engines will be dimensionally smaller than a four cycle for the same power output. The two cycle will tend to make peak power at a higher rpm and consequently less peak torque. What will work best depends on what you intend to do with the engine.